This invention relates to a composite blade, in which there is an essentially plate-like blade component with a composite-construction and retention members arranged in its rear part, which blade is intended to be installed in a special blade holder with the retention members remaining in the throat of the blade holder. The invention also relates to a method for manufacturing the blade.
At present composite blades are used in, for example, the doctors of paper machines. Rivets are installed in such composite-construction doctor blades, as they are in metal doctor blades too. The rivets are mainly intended to prevent the doctor blade from falling out of the blade holder. In addition, the rivets hold the doctor blade at the correct angle and in the correct position in the blade holder.
However, rivetting is a difficult and time-consuming stage of work, requiring special tools. In addition, before rivetting, holes must be made in the doctor blade, which is also laborious. Usually metal rivets are used, which must, however, be removed when the doctor blade is recycled or otherwise reused. Metal rivets also tend to jam during both installation and removal while they also scratch the blade holder. A scratched blade holder dirties more easily and aggravates the jamming of the metal rivets. Metal rivets or parts of them can also fall into the process and find their way into a roll nip, for example, with destructive consequences.
An object of the invention is to create a composite blade, which is simpler and more user-friendly than before, and which avoids the drawbacks of the state of the art. The invention is also intended to create a method for manufacturing the said composite blade more economically and with fewer work stages.
More specifically, a composite blade, in which there is an essentially plate-like blade component with a composite-construction and retention members arranged in its rear part is intended to be installed in a special blade holder with the retention members remaining in the throat of the blade holder. The composite blade is characterized in that the retention members are formed of a profiling arranged as a lateral extension of the blade component, which profiling extends essentially over the entire length of the blade and which is of the same piece as the blade component.
In the blade according to the invention, the rivets are replaced with a new kind of retention member, which is of the same material as the blade itself. Thus, the retention members neither scratch the blade holder nor jam. In addition, according to the method the said retention members are also formed during the manufacture of the blade. This entirely eliminates the stage of installing a separate retention member. Other advantages of the blade and method according to the invention are described in greater detail in connection with the disclosure.
The method for manufacturing a composite blade, in which method an essentially plate-like blade component is formed from composite material, and retention members are arranged in the rear part of the blade component to retain the blade in the throat of a special blade holder, is characterized in that a unified blank is formed from composite material, to that both the blade component and the profiling forming the retention members are manufactured simultaneously, and from which blank the blade with its retention members is detached.
These and other features and advantages of the invention will be more fully understood from the following detailed description of the invention taken together with the accompanying drawings.